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Screaming Gulf Myths: A Comment from Rog

Hollywood blockbuster ‘The Day After Tomorrow’ was an apocalyptic tale about the Gulf Stream — the ocean current which circulates warm water from the tropics to the Northern Hemisphere — being disrupted by global warming. In the following guest blog post, Rog summarises the latest research findings from Richard Seager on the Gulf Stream. This research suggests even if the Gulf Stream slows, New York won’t freeze over.

Oh well, I enjoyed the movie.

Rog writes:

There has been considerable speculation that changes to the body of water known as the “Gulf Stream” can alter climates on a local and global scale. Tim Flannery in his book ‘The Weather Makers’ speculates that the sudden drop of five degrees centigrade in Greenland ice cores was due to changes in the flow of the Gulf Stream.

Tim Flannery then goes on to state that changes to the Gulf Stream constitute a “tipping point” in global climate change.

The Pentagon shares Flannery’s views, in a study published in 2003 they warned that changes to the direction of the flow of the Gulf Stream could result in northern latitudes becoming suddenly colder and tropics much warmer leading to floods of desperate immigrants. The study notes that: “The dramatic slowing of the thermohaline circulation is anticipated by some ocean researchers, but the United States is not sufficiently prepared for its effects, timing, or intensity”.

However, in a recent article in the American Scientist, Richard Seager from Columbia University’s Lamont-Doherty Earth Observatory disputes all these scenarios. He claims:

“..temperatures will not drop to ice-age levels, not even to the levels of the Little Ice Age, the relatively cold period that Europe suffered a few centuries ago. The North Atlantic will not freeze over, and English Channel ferries will not have to plow their way through sea ice. A slowdown in thermohaline circulation should bring on a cooling tendency of at most a few degrees across the North Atlantic—one that would most likely be overwhelmed by the warming caused by rising concentrations of greenhouse gases. This moderating influence is indeed what the climate models show for the 21st century and what has been stated in reports of the Intergovernmental Panel on Climate Change. Instead of creating catastrophe in the North Atlantic region, a slowdown in thermohaline circulation would serve to mitigate the expected anthropogenic warming!”

Note that Richard Seager’s revelation was not founded on any new evidence.

“..All Battisti and I did was put these pieces of evidence together and add in a few more illustrative numerical experiments. Why hadn’t anyone done that before? Why had these collective studies not already led to the demise of claims in the media and scientific papers alike that the Gulf Stream keeps Europe’s climate just this side of glaciation? It seems this particular myth has grown to such a massive size that it exerts a great deal of pull on the minds of otherwise discerning people.

This is not just an academic issue. The play that the doomsday scenario has gotten in the media—even from seemingly reputable outlets such as the British Broadcasting Corporation—could be dismissed as attention-grabbing sensationalism. But at root, it is the ignorance of how regional climates are determined that allows this misinformation to gain such traction.”

————————-

Comment/guest posts welcomed from others readers of this blog, email jennifermarohasy@jennifermarohasy.com .

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22 Responses to “Screaming Gulf Myths: A Comment from Rog”

  1. Comment from: Ann Novek


    To make things even more complicated, I’m pretty sure sea temperatures in the North Sea, North Atlantic and Barents Sea are increasing.

    But a cooling of Scandinavia with some degrees would make it “impossible” to live here.

    Regarding the Gulf Stream, I just want to mention it powerfulness. In northern Norway most ports are ice free during winter months( ports that are above the polar circle).

  2. Comment from: Luke


    Does this mean that Rog now believes in AGW and GCMs?

  3. Comment from: Ann Novek


    Have you heard about the Norwegian “Doomsday vault”?

    The room is designed to hold around 2 million seeds, representing all varieties of the world’s crops. It is built to safeguard the world’s food supply against nuclear war, climate change, terrorism, rising sea levels, earthquakes and the ensuing collapse of electricity supplies.

    It will not be permanently manned, but “the mountains are patrolled by polar bears”.

    Read interesting article from New Scientist:

    http://www.newscientist.com/article/mg18925343.700.html

  4. Comment from: Ender


    rog – “However, in a recent article in the American Scientist, Richard Seager from Columbia University’s Lamont-Doherty Earth Observatory disputes all these scenarios. He claims:”

    Fair enough and he may be correct however there is evidence that the Younger Dryas was caused by an influx of fresh water into the Northern Atlantic ocean. There is clear physical evidence of the flows all over North America and a sudden and dramatic drop in temperatures.
    http://williamcalvin.com/1990s/1998AtlanticClimate.htm

    Possibly it is not clear cut and AGW could well mask out the effects of stalling the Atlantic circulation.

  5. Comment from: Pinxi


    Ann that article acknowledges some (unanswered) questions I’ve asked a couple of times previously on this blog about the security/vulnerability of global food supply given modern agricultural methods (limited, internationally common varieties and more concentrated seed supplies):

    “…growing concern about the safety of existing seed banks around the world. Many have been criticised for their poor security, ageing refrigeration systems and vulnerable electricity supplies. In the late 1980s, terrorists ransacked an international potato seed bank in the Peruvian Andes..”

  6. Comment from: rog


    Global Warming FAQ: What Every Citizen Needs to Know About Global Warming

    The Scare Stories

    Q: Is the world in danger of plunging into a new ice age, as in the 2004 movie The Day After Tomorrow?

    • No. The scenario presented in The Day After Tomorrow is physically impossible. While research does suggest that the Gulf Stream has switched on and off in the past, causing temperature drops in Europe, oceanographers are convinced that global warming does not present any such danger.10

    Q: Is the world in severe danger from sea level rise?

    • No. Research from Nils-Axel Mörner, professor of paleogeophysics and geodynamics at Stockholm University, demonstrates that current sea levels are within the range of sea level oscillation over the past 300 years, while the satellite data show virtually no rise over the past decade.11 The IPCC foresees sea-level rise of between 0.1 and 0.9 meters by 2100. The Earth experienced a sea-level rise of 0.2 meters over the past century with no noticeable ill effects.

    Another study relevant to this controversy is Zwally et al. (2005),12 which examined changes in ice mass “from elevation changes derived from 10.5 years (Greenland) and 9 years (Antarctica) of satellite radar altimetry data from the European Remote-sensing Satellites ERS-1 and -2.” The researchers report a net contribution of the three ice sheets to sea level of +0.05 ± 0.03 millimeters per year. CO2Science.Org puts this in perspective: “At the current sea-level-equivalent ice-loss rate of 0.05 millimeters per year, it would take a full millennium to raise global sea level by just 5 cm, and it would take fully 20,000 years to raise it a single meter.”

    http://www.cei.org/pdf/5430.pdf

  7. Comment from: Ender


    rog – “• No. The scenario presented in The Day After Tomorrow is physically impossible. While research does suggest that the Gulf Stream has switched on and off in the past, causing temperature drops in Europe, oceanographers are convinced that global warming does not present any such danger.10″

    Except it has happened in the past and the mechanism is an influx of fresh water which is happening at the moment with the arctic ice cap.

    “Q: Is the world in severe danger from sea level rise?”
    Yes because the greenland ice sheet is melting and it is on land.
    http://171.66.122.53/cgi/content/abstract/sci;289/5478/428
    http://sciencemag.org/cgi/content/abstract/297/5579/218

    which is a worry because the abstract says:
    “Surface Melt-Induced Acceleration of Greenland Ice-Sheet Flow

    H. Jay Zwally,1* Waleed Abdalati,2 Tom Herring,3 Kristine Larson,4 Jack Saba,5 Konrad Steffen6

    Ice flow at a location in the equilibrium zone of the west-central Greenland Ice Sheet accelerates above the midwinter average rate during periods of summer melting. The near coincidence of the ice acceleration with the duration of surface melting, followed by deceleration after the melting ceases, indicates that glacial sliding is enhanced by rapid migration of surface meltwater to the ice-bedrock interface. Interannual variations in the ice acceleration are correlated with variations in the intensity of the surface melting, with larger increases accompanying higher amounts of summer melting. The indicated coupling between surface melting and ice-sheet flow provides a mechanism for rapid, large-scale, dynamic responses of ice sheets to climate warming.”

    Sorry rog your Global Warming FAQ does not fit the facts.

  8. Comment from: Luke


    However heatwaves, droughts, floods, changes in pest distributions, and increased tropical storm intensities are more of a concern. Some of these effects are underway already.

  9. Comment from: rog


    There are facts and there are Enders facts;

    http://www.publications.parliament.uk/pa/ld200506/ldselect/ldeconaf/12/12we18.htm

  10. Comment from: rog


    Here is another one Ender;

    Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992–2002

    ABSTRACT. Changes in ice mass are estimated from elevation changes derived from 10.5 years (Greenland) and 9 years (Antarctica) of satellite radar altimetry data from the European Remote-sensing Satellites ERS-1 and -2. For the first time, the dH/dt values are adjusted for changes in surface elevation resulting from temperature-driven variations in the rate of firn compaction.

    The Greenland ice sheet is thinning at the margins (–42 Æ 2Gta –1 below the equilibrium-line altitude (ELA)) and growing inland (+53Æ 2Gta –1 above the ELA) with a small overall mass gain (+11 Æ3Gta –1 ; –0.03mma –1 SLE (sea-level equivalent)).

    The ice sheet in West Antarctica (WA) is losing mass (–47 Æ4Gta –1 ) and the ice sheet in East Antarctica (EA) shows a small mass gain (+16 Æ11Gta –1 ) for a combined net change of –31 Æ12Gta –1 (+0.08mma –1 SLE).

    The contribution of the three ice sheets to sea level is +0.05 Æ 0.03mma –1 .

    The Antarctic ice shelves show corresponding mass changes of –95 Æ11Gta –1 in WA and +142Æ10Gta –1 in EA.

    Thinning at the margins of the Greenland ice sheet and growth at higher elevations is an expected response to increasing temperatures and precipitation in a warming climate.

    The marked thinnings in the Pine Island and Thwaites Glacier basins of WA and the Totten Glacier basin in EA are probably ice-dynamic responses to long-term climate change and perhaps past removal of their adjacent ice shelves.

    The ice growth in the southern Antarctic Peninsula and parts of EA may be due to increasing precipitation during the last century.

    http://neptune.gsfc.nasa.gov/publications/pdf/pubs2005/Zwally%20-%20Mass%20changes%20of%20the%20Greenland.pdf

  11. Comment from: Davey Gam Esq.


    Wow! I’m confused. Are we going to freeze or boil? Drown or die of thirst? Or just adapt to changing climate as we always have in the past? Can somebody put all this in strip cartoon form for people like me?

  12. Comment from: Ender


    rog – the link you provided is interesting however the facts that are provided by this author are contradicted by other data. None of the authors papers appear to be published in peer reviewed publications so you or I cannot vouch for their accuracy.

    Some quotes:
    “The international organisations hosting the true specialists on sea level changes are to be found with the INQUA commission on sea level changes and the IGCP special projects on sea level changes.”

    This is just plain wrong – the specialists are:
    http://www.pol.ac.uk/psmsl/programmes/gloss.info.html

    “The Global Sea Level Observing System (GLOSS) is an international programme conducted under the auspices of the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM) of the World Meteorological Organisation (WMO) and the Intergovernmental Oceanographic Commission (IOC) (see http://www.jcommweb.net). GLOSS aims at the establishment of high quality global and regional sea level networks for application to climate, oceanographic and coastal sea level research. The programme became known as GLOSS as it provides data for deriving the ‘Global Level of the Sea Surface’.

    The main component of GLOSS is the ‘Global Core Network’ (GCN) of 290 sea level stations around the world for long term climate change and oceanographic sea level monitoring. The present definition of the GCN (the definition is modified every few years) is called GLOSS02. ”

    “In the last 10-15 years, we see no true signs of any rise or, especially, accelerating rise (as claimed by IPCC), only a variability around zero. This is illustrated in Fig 3. ”

    This is contradicted by several studies:
    Topex Poseidon satellite measurments http://sealevel.colorado.edu/
    http://www.sciencemag.org/cgi/content/short/310/5747/456
    This is an explanation of th differing methods of data collection.
    http://sealevel.jpl.nasa.gov/newsroom/features/200606-1.html
    Nobody else I could find agrees with the ’tilt back’ measurement that the author states. This does not seem to be peer reviewed and would need confirming.

    Facts may be facts rog but did you check them?

  13. Comment from: Ian Mott


    This has already been covered on this site, see;
    Ian Mott on Googling the ‘Atantic Conveyor’ http://www.jennifermarohasy.com/blog/archives/001060.html – 45k

    The realistic volume of melt water is highly unlikely to make any impact on the volume of circulating water in the North Atlantic.

    And it would be self defeating. The moment the temperature begins to drop (into the projected ice age), the supply of meltwater from the Greenland Ice Sheet will drop. The imagined causal agent will have ended. End of fantasy.

  14. Comment from: Ann Novek


    OK everyone. Maybe all this stuff will be less confusing in September.

    Some questions will certainly be answered when leading scientists involved in various aspects of research on the Nort Atlantic will participate in a symposium in Iceland regarding climate change and ocean currents.

    Purpose : Assessing the current state of knowledge on ocean currents, climate and ecosystems in the North Atlantic, and their interactions, bearing in mind the risk of change in the system due to climate change. Identifying priority future research tasks in these fields, so that we may further improving our understanding of the system, which would help assessing risks and enlighten policy decisions.

  15. Comment from: Luke


    You guys need to get updated – climate change processes are accelerating.

    Science 24 March 2006:
    Vol. 311. no. 5768, pp. 1747 – 1750
    DOI: 10.1126/science.1115159
    REPORTS
    Paleoclimatic Evidence for Future Ice-Sheet Instability and Rapid Sea-Level Rise
    Jonathan T. Overpeck,1* Bette L. Otto-Bliesner,2 Gifford H. Miller,3 Daniel R. Muhs,4 Richard B. Alley,5 Jeffrey T. Kiehl2
    Sea-level rise from melting of polar ice sheets is one of the largest potential threats of future climate change. Polar warming by the year 2100 may reach levels similar to those of 130,000 to 127,000 years ago that were associated with sea levels several meters above modern levels; both the Greenland Ice Sheet and portions of the Antarctic Ice Sheet may be vulnerable. The record of past ice-sheet melting indicates that the rate of future melting and related sea-level rise could be faster than widely thought.

    Recent rates of sea-level rise (2.6 ± 0.04 mm/year) (29) are already nearing the maximum average rate (3.5 mm/year) projected to occur over the next 1000 years by the IPCC (2). This anticipated rate is substantially less than the 11 mm/year average rate of sea-level rise measured for the last deglaciation between 13,800 and 7000 years ago (30). As mentioned earlier, however, the penultimate deglaciation, culminating with the LIG sea-level high stand 4 to >6 m above that of the present day, was driven by a substantially larger northern high latitude summertime insolation anomaly (Fig. 1). It seems likely, therefore, that ice-sheet melting leading to the LIG sea-level rise should have been at least as fast as the sea-level rise (11 mm/year) associated with the close of the last glacial period. Although a well-constrained record of sea-level rise leading to the LIG high stand is not yet available, there is well-dated yet controversial coral evidence that sea-level rise over this interval may have occurred at rates higher than 20 mm/year, perhaps right up to the LIG sea-level high stand (31). This makes sense given the much higher insolation (and warming) anomaly at this time and also the very real possibility that a LIG shrinkage of the WAIS (21) may be required to explain the large amount of sea-level rise above that of the present day at that time. Other recent paleo–sea-level studies indicate that very rapid sea-level rise is indeed possible (32).
    Our analysis, as well as ongoing changes in coastal Antarctica, are at least suggestive that the WAIS can indeed shrink rapidly as originally envisioned by Mercer (21). Given that there was no positive summer (melt-season) insolation anomaly at high southern latitudes in the several millennia before 129,000 years ago, it appears that two factors may have led to a LIG collapse of the WAIS (or perhaps portions of the EAIS). The first may have been the sea-level rise associated with pre-129,000 to 128,000 years ago GIS melting, and the second factor may have been shallow ocean warming around and under the Antarctic ice shelves that buttress portions of the Antarctic Ice Sheet. Sea-level rise seems to have had minor effects on the WAIS during the most recent deglaciation (33), but perhaps the greater speed of sea-level rise into the LIG compared with that from the Last Glacial Maximum (ca. 21,000 years ago) played a role by reducing the ability of isostatic rebound after grounding-line retreat to shallow sub–ice-shelf cavities and promote regrounding. As for the subsurface warming of south polar oceans, our LIG simulation showed modest (generally less than 0.5° but up to 1°C) warming in the upper 200 m of the ocean (Fig. 3) that would have further weakened ice shelves by thinning them from below; Shepherd et al. (34) find that such a modest warming increases sub–ice-shelf melt rates substantially, by perhaps 5 m/year up to 10 m/year. In our simulation, this small but notable warming was due to a positive springtime (October) insolation anomaly driving reduced sea ice and enhanced subsurface warming; note that this cool-season warming was not large enough to generate positive surface air temperature anomalies over the Antarctic in summer (Fig. 2). Even more dramatic ocean warming is likely in the future (Fig. 3), along with surface air temperature increases (in all seasons) and continued sea-level rise that could destabilize ice shelves that buttress the Antarctic Ice Sheet. Heat transport beneath ice shelves is highly complex, so caution is required, but the LIG may provide a conservative constraint on the future dynamics of the Antarctic Ice Sheet and particularly the WAIS. Moreover, the same parts of the Antarctic Ice Sheet may prove vulnerable even given increased precipitation [e.g., (35)].
    The ice-sheet origin of the LIG sea-level high stand in response to relatively small warming, together with recent results showing rapid response of ice to warming [e.g., (36, 37)], pose important challenges for ice-sheet modeling; whole ice sheet models do not yet incorporate important physical processes implicated in these changes (6, 20). Even in the absence of more-realistic models of ice-sheet behavior, it remains that ice sheets have contributed meters above modern sea level in response to modest warming, with peak rates of sea-level rise possibly exceeding 1 m/century. Current knowledge cannot rule out a return to such conditions in response to continued GHG emissions. Moreover, a threshold triggering many meters of sea-level rise could be crossed well before the end of this century, particularly given that high levels of anthropogenic soot may hasten future ice-sheet melting (28), the Antarctic could warm much more than 129,000 years ago (Figs. 2 and 3), and future warming will continue for decades and persist for centuries even after the forcing is stabilized (38, 39).

    1 Institute for the Study of Planet Earth, Department of Geosciences, and Department of Atmospheric Sciences, University of Arizona, Tucson, AZ 85721, USA.
    2 National Center for Atmospheric Research, Post Office Box 3000, Boulder, CO 80307, USA.
    3 Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, Campus Box 450, Boulder, CO 80309, USA.
    4 U.S. Geological Survey, Mail Stop 980, Box 25046, Federal Center, Denver, CO 80225, USA.
    5 Department of Geosciences and Penn State Ice and Climate Exploration Center, Pennsylvania State University, 0517 Deike Building, University Park, PA 16802, USA.

    Science 24 March 2006:
    Vol. 311. no. 5768, pp. 1754 – 1756
    DOI: 10.1126/science.1123785
    REPORTS
    Measurements of Time-Variable Gravity Show Mass Loss in Antarctica
    Isabella Velicogna1,2* and John Wahr1*
    Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment satellites, we determined mass variations of the Antarctic ice sheet during 2002–2005. We found that the mass of the ice sheet decreased significantly, at a rate of 152 ± 80 cubic kilometers of ice per year, which is equivalent to 0.4 ± 0.2 millimeters of global sea-level rise per year. Most of this mass loss came from the West Antarctic Ice Sheet.
    1 University of Colorado, Cooperative Institute for Research in Environmental Sciences and Department of Physics, University Campus Box 390, Boulder, CO 80309–0390, USA.
    2 Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300-233, Pasadena, CA 91109–8099, USA.

    Science 24 March 2006:
    Vol. 311. no. 5768, pp. 1756 – 1758
    DOI: 10.1126/science.1122112
    REPORTS
    Seasonality and Increasing Frequency of Greenland Glacial Earthquakes
    Göran Ekström,1* Meredith Nettles,2 Victor C. Tsai1
    Some glaciers and ice streams periodically lurch forward with sufficient force to generate emissions of elastic waves that are recorded on seismometers worldwide. Such glacial earthquakes on Greenland show a strong seasonality as well as a doubling of their rate of occurrence over the past 5 years. These temporal patterns suggest a link to the hydrological cycle and are indicative of a dynamic glacial response to changing climate conditions.
    1 Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA.
    2 Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.

    Also – out of interest – has Seager published his work in the literature.

    How do we explain the paleo data with the forams cores which shows the conveyor switching off.

    BTW – I hope Seager is right. His work is indeed most interesting. His degree of smugness is disturbing though.

    One can’t help but smile though as the usual suspects on the blog want to agree with this piece of climate modelling – why not agree with much more !!

  16. Comment from: Ender


    Ian – “The moment the temperature begins to drop (into the projected ice age), the supply of meltwater from the Greenland Ice Sheet will drop. The imagined causal agent will have ended. End of fantasy.”

    Ian you are thinking linear. The atmospheric system is chaotic and does not behave in this linear manner. The problem is with chaotic systems that have 2 or more ‘stable’ states they only need small triggers to shift from one to other.

    Some people suspect that this is the case with the ATC. We are in a warm/wet stable state at the moment. A small change in the ATC could be enough to tip us into the cold/dry stable state similar to the Younger Dryas which will continue until something takes us out of it.

    Perhaps AGW is enough to prevent this – no-one knows the answer to this.

    http://www.ncdc.noaa.gov/paleo/abrupt/story2.html

  17. Comment from: Ian Mott


    No Ender, I am thinking cause and effect.
    All the speculation in relation to the collapse of the Atlantic Conveyor/Thermohaline Circulation depend on assumptions about salinity changes due to excess fresh water being added to the system.

    The problem is that the volume of existing circulation in the North Atlantic is of such magnitude that the melting of the Greenland Ice Sheet is unlikely to produce any significant change to ocean salinity. And consequently, there can be only minimal change in water density.

    The proponents of this theory have clearly not bothered to cross check the theory with the actual volumes involved and their velocity of circulation.

    So all the other studies and miriad sites on the topic are pure crap until someone provides the actual numbers in a fully transparent way that can show the actual change in North Atlantic salinity/density over time.

    The only way the scenario might ever enter the realm of the possible is if the entire Greenland Ice Sheet were to melt in a single decade. And that rate of warming is nowhere on anyone’s credible radar.

  18. Comment from: Luke


    So Ian why does the paleo evidence indicate the conveyor has stopped in the past – whoops!

    And the ocean salinity IS currently changing despite your comments – it is responding.

  19. Comment from: Ender


    Ian – “The problem is that the volume of existing circulation in the North Atlantic is of such magnitude that the melting of the Greenland Ice Sheet is unlikely to produce any significant change to ocean salinity. And consequently, there can be only minimal change in water density.”

    No the whole volume of the North Atlantic is not the issue. There are certain downwelling points that are quite restricted in volume and could be disproportionally affected by the volume of fresh water from the polar ice caps. However you are completely correct that there is no real research showing that the volume of fresh water from the Arctic is sufficient to stall the current or that stalling the current would in the light of present warming put NE into deep freeze. Models do show that:
    “Also, in coupled Atmosphere-Ocean General Circulation Models the THC tends to weaken somewhat rather than stop, and the warming effects outweigh the cooling, even locally: the IPCC Third Annual Report notes that even in models where the THC weakens, there is still a warming over Europe [4]. Model runs in which the THC is forced to shut down do show cooling — locally up to 8 degrees Celsius [5] — although the largest anomalies occur over the North Atlantic, not over land.”

    So I would have to conclude that you are essentially correct. The Day After Tomorrow scenerio is pretty crap and I must admit to my shame I was taken in by the book “The Coming Global Superstorm” at least for the first few chapters. However when Atlantis etc was mentioned it dawned on me that perhaps the authors were a bit ‘new age’. Subsequent research into both the authors and the book made it clear that this book had as much chance of being true as the authors UFO book – sigh. The movie was absolute shite as well.

    However chaotic systems can still suprise us. There has been an observed weakening so let us hope that it does not behave chaotically.

  20. Comment from: Ian Mott


    Thank you, Ender, can I put your post on a plaque?

    One point, those few downwelling points are still fed by the conveyor and the speed of the Gulf Stream feeding the conveyor involves the equivalent of five or six complete circulations each year. It gets wider as the speed slows but the volume is essentially the same.

    And most interesting is the fact that the largest mass of fresh water in the NA is actually in the Gulf of St Laurence. It is where most of the land based melt water from Canada mixes with the Gulf Stream. And it is mixed very well due to eddies that can be more than 1.2Km deep.

    And it is the character and extent of this sort of mixing that also undermines the “ocean acidification” boogeyman. For it assumes that circulation of surface water does not extend any deeper than 100 metres.

  21. Comment from: Ender


    Ian – I researched what you said in the literature that I can understand, and it supported your position so naturally I wrote what I wrote.

    The mixing is what makes the ocean such a good CO2 sink. Without the oceans atmospheric CO2 would be much much higher. However if they warm then the can sink less CO2. I don’t think that ocean acidification depends on water not circulating.

    This model study assumes deep mixing of sea water
    http://www.stanford.edu/group/efmh/jacobson/2004JD005220.pdf

    and again in examining the Eocene Thermal Maximum
    http://adsabs.harvard.edu/abs/2004AGUFMPP11B0561Z
    the deep water is shown to have acidified.

  22. Comment from: Ian Mott


    Interesting, Ender. No time to look today but will do. The Brits Royal Society paper on acidification assumes no mixing deeper than 100 metres. Sorry, no time for URL either.

    But the other issue is of whether the degree of change in alkalinity is outside the normal range of variation between oceans and between ocean layers.